This is a proposal to use the National Death Index to determine 16 year mortality status of the 361,662 middle-aged men screened in 1973-75 for the Multiple Risk Factor Intervention Trial. These data will be used to study the persistence of associations of blood pressure, serum cholesterol and cigarette smoking with coronary, stroke and cancer mortality, to compare risk association with all cause and cause-specific mortality among Hispanics, white non-hispanics and blacks and to assess risk factor relationship with rare cancers and with conditions frequently mentioned on the death certificate but rarely specified as the underlying cause of death. Over 24,00 deaths have been identified in this cohort to date using the National Death Index through 12 years of follow-up. Death certificates have been collected and coded by nosologists for 23,778 (99%). Among these 23,778 deaths, 8,168 deaths are due to coronary heart disease; 788 deaths are due to stroke; 8,061 deaths are due to cancer; 844 deaths are due to digestive diseases; and 794 deaths are due to respiratory diseases. Among the cancers, we have recorded 2,657 due to lung, 1,043 due to a 10% increase in the number of deaths per year, that the four additional calendar years of follow-up proposed will bring the total number of decedents to over 40,000 approximately 11% of the total number of men screened. With such a large number of deaths, analyses of uncommon causes of death can be studied and their association with cholesterol, blood pressure, cigarette smoking, and race analyzed and documented. Recently acquired meteorological and demographic data for small areas will be used to search for possible relationship of such factors to variables into risk factor analyses. This data set on risk factors and mortality outcome is unparalleled with respect to size and to the high level of quality control imposed during data collection. These aspects make these data particularly valuable for long-term follow-up and analyses.